"""
Celery задачи для системных операций (бэкапы, очистка и т.д.)
"""

from celery import shared_task
import logging
from django.core.management import call_command
from django.conf import settings
import os

logger = logging.getLogger(__name__)


@shared_task
def backup_database():
    """
    Автоматическое создание бэкапа базы данных.
    Запускается через Celery Beat.
    """
    try:
        backup_dir = os.path.join(settings.BASE_DIR.parent, 'backups', 'database')
        retention_days = int(os.getenv('BACKUP_RETENTION_DAYS', '30'))
        
        logger.info(f'Starting database backup to {backup_dir}')
        
        call_command(
            'backup_database',
            output_dir=backup_dir,
            retention_days=retention_days,
            compress=True,
        )
        
        logger.info('Database backup completed successfully')
        return 'Database backup completed'
        
    except Exception as e:
        logger.error(f'Error creating database backup: {e}', exc_info=True)
        raise


@shared_task
def cleanup_old_backups():
    """
    Очистка старых бэкапов.
    Удаляет бэкапы старше указанного количества дней.
    """
    try:
        from datetime import timedelta
        from django.utils import timezone
        import glob
        
        backup_dir = os.path.join(settings.BASE_DIR.parent, 'backups', 'database')
        retention_days = int(os.getenv('BACKUP_RETENTION_DAYS', '30'))
        cutoff_date = timezone.now() - timedelta(days=retention_days)
        
        if not os.path.exists(backup_dir):
            logger.warning(f'Backup directory does not exist: {backup_dir}')
            return 'Backup directory does not exist'
        
        deleted_count = 0
        total_size_freed = 0
        
        # Ищем все файлы бэкапов
        backup_patterns = [
            os.path.join(backup_dir, 'db_backup_*.sql'),
            os.path.join(backup_dir, 'db_backup_*.sql.gz'),
        ]
        
        for pattern in backup_patterns:
            for backup_file in glob.glob(pattern):
                try:
                    file_mtime = os.path.getmtime(backup_file)
                    file_date = timezone.datetime.fromtimestamp(file_mtime, tz=timezone.utc)
                    
                    if file_date < cutoff_date:
                        file_size = os.path.getsize(backup_file)
                        os.remove(backup_file)
                        deleted_count += 1
                        total_size_freed += file_size
                        logger.info(f'Deleted old backup: {os.path.basename(backup_file)}')
                except Exception as e:
                    logger.error(f'Error deleting backup {backup_file}: {e}')
        
        size_mb = total_size_freed / (1024 * 1024)
        logger.info(f'Cleanup completed: {deleted_count} backups deleted, {size_mb:.2f} MB freed')
        
        return f'Deleted {deleted_count} old backups, freed {size_mb:.2f} MB'
        
    except Exception as e:
        logger.error(f'Error cleaning up old backups: {e}', exc_info=True)
        raise